For me it's all in the eyes, in this picture it's clear you are not confident within just by looking at your eyes. Try thinking about your happiest moment just before you take the picture, like the whole world is looking and you don't give a shit. When you remember your beauty within it will be reflected on your face and in your eyes. Arrogance is ugly, confidence is beauty. You are a very pretty girl and shouldn't be so concerned about your looks, do what you need to do to feel beautiful to yourself, not what others ideals are.